In older machines, large pages are =2MB, and of you have enough of them, let's say 10G, you may use in my.cnf
and innodb correctly allocates from this faster, never swappable memory pool.
BUT, if the machine is newer, and you booted with a kernel command line with
Then you only need to allocate 10 pages to get 10GB of memory. This makes memory managent much faster
however, Innodb get confused. if you add
it will allocate 50G from the OS, verifiable doing
cat /proc/meminfo | grep HugePages
yet internally it will think it has only 5G, the rest is wasted.
I have a box ready to show the issue to Elena is she wants to see it. I have seen the issue in many boxes.